1. Field of the Invention
The present invention pertains to the closure of flexible packages, such as plastic bags, and in particular to fastener closures employing sliders.
2. Description of the Related Art
With the recent emphasis in providing consumers with bulk quantities of various commodities, such as food products, reclosable packages have become increasingly popular. One of the most popular means of providing reclosability is to employ zippers of various types, particularly zippers which are compatible with flexible packages of plastic film construction. Manufacturers of food products and other commodities are concerned with filling the contents of a flexible package as quickly and economically as possible. It is important that the opening provided by the fastener be made as large as practically possible. Consumers or other end users also prefer large sized openings for easy extraction of products from the package interior. Even with large openings, however, products within the package may interfere with fastener operation when product poured or otherwise dispensed from the package becomes entrained in the fastener components.
Other improvements to flexible reclosable packages are being sought. For example, when handling products comprised of numerous small pieces, such as shredded cheese or cereal, for example, it is generally desirable to have the package formed into a pouch which is open at one end, or along one side, so as to allow product to be poured or shaken through the reclosable opening. It is desirable that the product be allowed to freely flow past the reclosable opening. Preferably, the path taken by the product within the package should be made as smooth as possible.
Although improvements have been made in the art of plastic welding and joining, manufacturers of consumer products employing high speed production techniques are continually seeking improved package forming methods and equipment. Concern has been focused on the formation of stop members which limit the travel of a sliding closure traveling along fastener tracks. Any reduction in the time needed to form these and other package features can result in substantial cost savings.
It is an object of the present invention to provide a shrouded flexible package with an improved fastener closure.
Another object of the present invention is to provide reclosable packages having fastener sliders which are protected during shipment and display, and afterwards, when the package contents are poured out or otherwise extracted.
A further object of the present invention is to provide a shrouded reclosable package having improved arrangements for hanging display.
Yet another object of the present invention is to provide a shrouded reclosable plastic package having a slider fastener with improved containment of the slider in a manner which also optimizes the size of the bag opening.
A further object of the present invention is to provide a shrouded plastic bag having a slider fastener with an improved end or xe2x80x9ccrushxe2x80x9d seal of the fastener tracks.
These and other objects of the present invention are attained in a reclosable flexible package comprising opposed front and rear panels that have sides joined together to form an interior and a package opening communicating with said interior. The reclosable flexible package has first and second interlockable fastener tracks configurable in an interlocked, closed position and an unlocked open position. It has a slider movable along fastener tracks to configure tracks in interlocked position to close opening and to configure fastener tracks in unlocked position so as to allow access through opening to package interior. The fastener tracks have opposed ends located adjacent opposed sides of front and rear panels. The stops adjacent ends of fastener tracks interfere with and prevent travel of slider beyond fastener tracks. A side seal of pre-selected width joins together one side of front and rear panels. A shroud covers slider and at least the major portion of fastener tracks. Weakening portions extend adjacent fastener tracks and severe the remainder of reclosable flexible package.
It has been determined that, in a practical commercial environment, it is difficult to employ conduction heat sealing techniques to form the slider stop. It is preferred that the stop be formed using ultrasonic sealing techniques, as these afford greater control over dimension and shape. This is important when the maximum number of advantages accorded the present invention are being sought, since the mass, and particularly the frontal surface area of the stop is reduced to the greatest extent possible.